Study: Neanderthals Had Capacity to Produce Human-Like Speech
Neanderthals evolved the auditory capacities to support a vocal communication system as efficient as modern human speech, according to new research led by Universidad de Alcalá scientists.
The linguistic capacities in Neanderthals have long been an area of active research and debate among scientists, albeit with little resolution.
The last two decades have seen increasing archaeological discoveries documenting complex behaviors in this sister species to Homo sapiens. These have been linked to the possible presence of language, since it seems reasonable to suggest that such behaviors require the presence of a complex and efficient oral communication system.
Nevertheless, a different point of view maintains that the distinctive features of human language, absent in other organisms, include a symbolic element as well as a recursive syntactic process called merge.
This latter process, at its simplest, uses two syntactic elements and assembles them to form a set and is argued to be exclusive to Homo sapiens and to have appeared no earlier than 100,000 years ago.
Tracing the presence of symbolism and syntactic processes in the course of human evolution currently lies outside the realm of possibility in paleontology.
Nevertheless, the study of human fossils can prove key to determining whether past human species, and in particular the Neanderthals, possessed the anatomy necessary to produce and perceive an oral communication system as complex and efficient as human speech, the usual vehicle for language.
In other words, although paleontology cannot study the evolution of the ‘software’ of language it can contribute to our understanding of the evolution of the ‘hardware’ of speech.
“For decades, one of the central questions in human evolutionary studies has been whether the human form of communication, spoken language, was also present in any other species of human ancestor, especially the Neanderthals,” said Professor Juan Luis Arsuaga, a researcher at the Centro Mixto (UCM-ISCIII) de Evolución y Comportamiento Humanos and the Departamento de Geodinámica at the Universidad Complutense de Madrid.
Using high-resolution CT scans, Professor Arsuaga and his colleagues created 3D models of the ear structures of Homo sapiens, Neanderthals, and the Sima de los Huesos hominins, considered ancestors of the later Neanderthals.
They then entered the new data into a software-based model, developed in the field of auditory bioengineering, to estimate the hearing abilities up to 5 kHz, which encompasses most of the frequency range of modern human speech sounds.
Compared with the Sima de los Huesos hominins, Neanderthals showed slightly better hearing between 4-5 kHz, resembling modern humans more closely.
In addition, the researchers calculated the frequency range of maximum sensitivity, technically known as the occupied bandwidth, in each species.
“The occupied bandwidth is related to the communication system, such that a wider bandwidth allows for a larger number of easily distinguishable acoustic signals to be used in the oral communication of a species,” they explained.
“This, in turn, improves the efficiency of communication, the ability to deliver a clear message in the shortest amount of time.”
The Neanderthals had a wider bandwidth compared with their ancestors from Atapuerca, more closely resembling modern humans in this feature.
“This really is the key. The presence of similar hearing abilities, particularly the bandwidth, demonstrates that the Neanderthals possessed a communication system that was as complex and efficient as modern human speech,” said Professor Mercedes Conde-Valverde, a researcher in the Cátedra de Otoacústica Evolutiva y Paleoantropología at the Universidad de Alcalá.
“One of the other interesting results from the study was the suggestion that Neanderthal speech likely included an increased use of consonants,” said Professor Rolf Quam, a researcher in the Department of Anthropology at the Binghamton University, the Division of Anthropology at the American Museum of Natural History, the Universidad de Alcalá, and the Centro Mixto (UCM-ISCIII) de Evolución y Comportamiento Humanos.
The team’s results show that Neanderthals had a similar capacity to us to produce the sounds of human speech, and their ear was ‘tuned’ to perceive these frequencies.
This change in the auditory capacities in Neanderthals, compared with the ancestral Sima de los Huesos hominins, parallels archaeological evidence for increasingly complex behavioral patterns, including changes in stone tool technology, domestication of fire and possible symbolic practices.
“These results are particularly gratifying. We believe, after more than a century of research into this question, that we have provided a conclusive answer to the question of Neanderthal speech capacities,” said Dr. Ignacio Martinez, a researcher at the Centro Mixto (UCM-ISCIII) de Evolución y Comportamiento Humanos and the Departamento de Geodinámica at the Universidad Complutense de Madrid.
The findings were published in the journal Nature Ecology & Evolution.
M. Conde-Valverde et al. Neanderthals and Homo sapiens had similar auditory and speech capacities. Nat Ecol Evol, published online March 1, 2021; doi: 10.1038/s41559-021-01391-6